JP2607028Y2 - Digital oscilloscope - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital oscilloscope, and more particularly, to a digital oscilloscope having means for re-sampling waveform data of a specific portion with respect to waveform data captured in a digital memory and displaying the sampled data as a secondary waveform. It is about.

[0002]

2. Description of the Related Art For example, when evaluating an electric signal or the like obtained by scanning a screen like a TV signal, it is necessary to pay attention to a specific portion on the screen and evaluate its characteristic value. Also, read the value by scrolling on the screen displaying the waveform of the data stored in the digital memory,
Observers observed specific parts on the screen visually. For example, any line in the y-axis direction on the screen
When evaluating the change in luminance along
Out of the data stored in the
Need to read the data value. However, in such a measurement, the measurement operation must be repeated several to several hundred times.

[0003]

The present invention solves such a problem, and automatically extracts a specific portion of a stored waveform by extracting the specific portion as a secondary sampling point .
It is an object to realize a digital oscilloscope capable of observing a waveform .

[0004]

SUMMARY OF THE INVENTION The present invention provides an analog / digital converter for converting an input analog signal into a digital signal, a waveform memory for storing a signal from the analog / digital converter, and a memory for storing the signal. waveform display means for displaying data on the display screen as the waveform of the display
For a repetitive waveform on the screen, a specific point of the repetitive waveform
And designating means for designating , the waveform display means,
The specific point of the repetitive waveform specified by the specifying means
From the waveform memory at the cycle of the repetitive waveform.
To create a waveform with only specific points and display it on the screen.
This is a digital oscilloscope characterized by observing a change at a specific point for each repetitive waveform .

[0005]

[Action] Once using the stored waveform data, by performing the secondary sampling the set sample values facilitates observation of the waveform of the specific part.

[0006]

FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 1 denotes an AD converter, which converts an input analog signal into a digital signal. 2 is a timing circuit, and 3 is a waveform memory. The timing circuit 2 outputs a signal for controlling the timing of AD conversion and the timing of writing data in the waveform memory 3. The waveform memory 3 stores
The digital data output from the converter 1 is stored under the control of the timing circuit 2. A data processing circuit 4 reads data stored in the waveform memory 3 and performs arithmetic processing such as averaging processing and peak detection processing. 5
Is a display processing circuit for converting data output from the data processing circuit 4 into display data.

Reference numeral 6 denotes a display device for displaying the display data output from the display processing circuit 5. Reference numeral 7 denotes a secondary sampling point designating circuit, and reference numeral 8 denotes a man-machine interface, which converts a signal a for designating a secondary sampling point and an operation of an operator for designating a secondary sampling point into an electric signal. Based on the signal input from the man-machine interface 8, the secondary sampling point designating circuit 7
To calculate which specific data among the data stored in the data to be displayed as secondary data, and to display a signal a specifying a secondary sampling point and a secondary sampling point on a display screen. The signal b is output to the data processing circuit 4 and the display processing circuit 5. Specifically, the waveform memory 3
The function of reading data at the designated address and the read data are constituted by a register or the like for storing the data. Reference numeral 8 denotes a man-machine interface that converts a setting input from the outside into an electric signal.

FIG. 2 shows the operation in such a configuration.
This will be specifically described with reference to the waveform diagram of FIG. In FIG.
(A) is obtained by displaying the data stored in the waveform memory 2, (b), the finger portion for secondary sampling
This is a display of a square wave required for setting.

The waveform memory 3 has a capacity capable of storing data as M words. Of these, the capacity that can be displayed by the display 6 is m words. The so-called display is a state in which switching is performed in a window of m words. For example, it is assumed that the stored M-word data is observed again at the point A shown in FIG. 2 in a certain trigger state.

In such a state, at the same time when the point A is selected by the man-machine interface 8, the rectangular wave P shown in FIG. 2 is displayed, and the rectangular wave P is displayed so as to correspond to one cycle of the displayed waveform. Specify the period. This rectangular wave P is a part for performing secondary sampling,
Select on the man-machine interface 8. The period of the rectangular wave P can be arbitrarily adjusted by the man-machine interface 8. The phase can also be changed. By these adjustment operations, the rising edge of P is adjusted to a predetermined position. This designation is performed by inputting a number or operating a soft key on the screen of the display unit 6. Further, the repetition period of the waveform stored in the waveform memory 3 can be calculated and displayed by a data processing circuit 4 or an operation of a microprocessor which is not shown in FIG. The cycle of the rectangular wave P can be designated by a numerical value. Alternatively it is also possible to adjust the period of P as the period of the P coincides with the period of the original waveform when it is displayed.

In the secondary sampling point designating circuit 7, when a signal indicating that secondary sampling is to be performed is input to the man-machine interface 8, the data of the waveform memory 3 corresponding to the rising portion of the rectangular wave P (the raster data of the preceding and succeeding rasters). (Including changes in data) and store it as secondary sampling data.

The data processing circuit 4 inputs the secondary sampling data detected by the secondary sampling point indicating circuit 7 and reads the waveform data from the waveform memory 3 again.
At this time, since the repetition cycle of the waveform stored in the waveform memory 3 is already in the data processing circuit 4, the address of the secondary sampling point data at the point A which is the rising edge of the rectangular wave P is sequentially determined. Can be performed. The waveform data for each address is read out for N words, the arithmetic processing of these N words of data is performed, and then output to the display processing circuit 5 for displaying the waveform. Specifically, the data processing circuit 4 generates the address, sequentially reads data from the waveform memory 3, performs predetermined data processing, converts a display signal by the display processing circuit 5, and displays the converted signal on the display 6. I do. At this time, the characteristic value in the vertical or time axis direction can be measured by the cursor.

When the rectangular wave P is set on the display screen in this manner, data corresponding to the time of the rising edge of the rectangular wave P is extracted from the data displayed in FIG. A waveform as shown in FIG. 3 is displayed as secondary sample data (specifically, it corresponds to a set of points A). Since the period of the rectangular wave P is N words on the waveform memory 3, (M / N) secondary sample data is obtained. In this way, the data of the waveform memory 3 can be measured very simply and quickly by a simple operation.

In such a configuration, as shown in FIG. 2, not only the point A is indicated by a rectangular wave,
As shown in FIG. 4, a secondary sample point can be designated by an impulse waveform or a mark sequence. In this case, the rising part of the impulse waveform and the raster line at the tip of the mark are recognized as the rising part of the rectangular wave shown in FIG. Further, as shown in FIG. 5, not only the secondary sample point data having a fixed period but also the secondary sample point data having a complicated repetition period can be specified. Also in this case, the data of the portion designated by each impulse wave is secondarily sampled, and the data processing circuit 4 calculates an address for reading out a plurality of secondary sample point data based on the data. become.

[0015] The configuration of the present invention can be used as hardware.
It can also be realized as software operation by a microprocessor. Even when a plurality of channels are provided, the same operation can be performed by providing a waveform memory for each channel. The designation of the secondary sampling point data is not the one shown in FIGS. 2, 4 and 5, and the same operation can be performed by using the waveform of the same channel or another channel as the sampling designation waveform. It is. For example, an operation of measuring a characteristic value such as sensitivity unevenness of a TV camera or the like on a designated portion of a screen is also possible. Such a measurement is particularly effective in a waveform measuring apparatus having a large-capacity waveform memory and capable of recording with a long record length.

[0016]

As described [devised effect] above in detail, the present invention, the data in the waveform memory is a high capacity, by performing the secondary sampling the set sample values, specified portion Observation of the waveform becomes easy.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of the present invention.

FIG. 3 is an explanatory diagram for explaining the operation of the present invention;

FIG. 4 is an explanatory diagram for explaining the operation of the present invention.

FIG. 5 is an explanatory diagram for explaining the operation of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 A / D converter 2 Timing circuit 3 Waveform memory 4 Data processing circuit 5 Display processing circuit 6 Display device 7 Secondary sample point designating circuit 8 Man-machine interface circuit

Claims (1)

(57) [Scope of request for utility model registration] An analog / digital converter for converting an input analog signal into a digital signal, a waveform memory for storing a signal from the analog / digital converter, and data on the waveform memory as a waveform on a display screen. Waveform display means for displaying on the display screen;
Of comprising a designating means for designating a specific point, Repetitive the waveform display unit, designated by the designation unit
The specified point of the repetitive waveform is
Reads at the cycle of the shape, creates a waveform only at specific points,
Display on the screen and change the specific point for each repetitive waveform
A digital oscilloscope characterized by observing .